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  • Nuclear Radiationnuclear reactions different from other reactions ________________________________________________________________________________*

  • Nuclear Radiationin 1895 German physicist Wilhelm Roentgen discovered that invisible rays were emitted when electrons bombarded the surface of certain materialsnamed these emissions _________________________Marie & Pierre Curie isolated the 1st radioactive material Marie Curie came up with word radioactiveCuries won Nobel Prize in 1903 & Marie won another in 1911*

  • Nuclear Radiationrecall from Chapter 4nucleus made up of protons and neutronsatomic # (_____) is the number of protonsmass # (______) is the protons + neutrons______________________ are atoms with the same atomic number but different atomic masses (different # of neutrons)nuclides represented byA = Mass # Z = Atomic #X = Element Symbol *

  • Nuclear Radiationexample carbon series of isotopes

    carbon12

    carbon13

    carbon14*

  • Nuclear Radiationisotopes of atoms with unstable nuclei are called _______________________these radioisotopes emit radiation to try & get a more stable atomic configurationwhile undergoing radioactive decay, atoms lose energy by emitting radiationthree most common types of radiation are alpha (), beta (), & gamma ()*

  • Nuclear RadiationTable 24.2 Pg. 861*

  • Nuclear RadiationFigure 24.2 Pg. 862*

  • Nuclear Radiationalpha particles () have same composition as helium atoms (2 protons & 2 neutrons) with a +2 charge ( )

    Figure 24.3 Pg. 862*

  • Nuclear Radiationbeta particles ( or e) are very fast moving electrons with a 1 charge ( )emitted when a neutron converts to a protonFigure 24.4 Pg. 863*

  • Nuclear Radiationgamma rays () are high energy photons with no mass or charge ( )always accompanies other nuclear decays*

  • Nuclear Radiationxrays are a form of high-energy electromagnetic radiationnot produced by radioactive sourcesemitted from certain materials in an excited state*

  • Penetrating Powerthe more energy content of the radiation, the more damage it can causedifferent rays can penetrate different levels of the human body ( stopped by skin, can penetrate 1cm, are highly penetrating) *

  • Radioactive Decayall decay (except gamma radiation) involves the conversion of an element into another element______________________________ when an atoms atomic number is alteredprotons & neutrons also called ___________________nucleons held in the nucleus by the strong nuclear force*

  • Radioactive Decay________________________________________ acts on subatomic particles that are extremely close together & it overcomes the electrostatic repulsion among protonsFigure 24.6 Pg. 865*

  • Radioactive Decayatoms undergo radioactive decay to gain stabilitytypes of decay ___________________________ ________________________________________ ________________________________________

    *

  • Radioactive Decaybeta decay decreases the # of neutrons in an atom by converting it to a protonresults in a new atom with no loss in the _______________________ & gain of 1 in _______________________

    Figure 24.8a Pg. 867*

  • Radioactive Decayalpha decay decreases the # of neutrons & protonsresults in a new atom with a loss of 4 in the _______________________ & loss of 2 in _______________________ Figure 24.8b Pg. 867*

  • Radioactive Decay_______________________ a decay process that involves the emission of a positron from the nucleus to reduce protons_______________________ a particle with the same mass as an electron, but opposite chargeresults in a new atom with no loss in the _______________________ & loss of 1 in _______________________Figure 24.9a Pg. 868*

  • Radioactive Decay_____________________ occurs when the nucleus of an atom draws in a surrounding electron & combines it with a proton to form a neutronresults in a decrease in protonsresults in a new atom with no loss in the _____________________ & loss of 1 in _____________________ Figure 24.9b Pg. 868*

  • Radioactive DecayTable 24.3 Pg. 868*

  • Radioactive Decaynuclear reactions are expressed by a balanced nuclear equationin nuclear equations mass numbers & charges are conserved treat the arrow like an equal sign & make sure the mass numbers & atomic numbers equal on both sides of the equation*

  • Radioactive DecayExamples: Write balanced nuclear equations for the following processescarbon11 produces a positronbismuth214 produces a particleneptunium237 produces an particleUranium-235 undergoes electron capturesilver116 produces a particlebismuth211 produces an particle and 3 gamma rays*

  • Radioactive DecayExamples: carbon11 produces a positron

    _______________________________________________________________________________________*

  • Radioactive DecayExamples: bismuth214 produces a particle

    _______________________________________________________________________________________*

  • Radioactive DecayExamples: neptunium237 produces an particle

    _______________________________________________________________________________________*

  • Radioactive DecayExamples: uranium235 undergoes electron capture

    *_______________________________________________________________________________________

  • Radioactive DecayExamples: silver116 produces a particle

    *

  • Radioactive Decay*Examples: bismuth211 produces an particle and 3 gamma rays

  • Radioactive Decay Seriesmany times a radioactive nucleus can not create a stable (nonradioactive) atom through a single decay ___________________________________________ a series of nuclear reactions that begins with an unstable nucleus & results in the formation of a stable nucleusmost well known series is of uranium238 to lead206 (it takes 14 different radioactive decay steps)*

  • Radioactive Decay SeriesFigure 24.10 Pg. 870*

  • Radioactive DecayExample: The first 4 steps of uranium238 decaying into lead206 are alpha, beta, beta, alpha. Write the nuclear equation for each step.

    .

    .

    .

    .*

  • Radioactive Decay Ratesto measure the speed (rate) of decays, scientists use halflives____________________________ the amount of time required for of a radioisotope to decay into its products*

  • Radioactive Decay Ratesevery radioactive nuclide has a specific half-lifefrom seconds to billions of yearsexample: gold198 (used for cancer treatment) has a halflife of 2.7 dayshow much would remain of a 50g implant after 1 week?*

  • Radioactive Decay RatesExample: the halflife of strontium90 is 29 years; if you had 10.0 g of strontium90 today, 29 years from now you would have 5.0 g leftTable 24.4 Pg. 871*

  • Figure 24.11 Pg. 871*

  • Radioactive Decay Rateseach radioisotope has a specific halfliferange from seconds to billions of years

    Table 24.5 Pg. 871*

  • Radioactive Decay RatesExample: Krypton-85 is used in indicator lights of appliances. The half-life of krypton-85 is 11 years. How much of a 2.000 mg sample remains after 33 years?1st look at what is known/unknown:initial amount = 2.000 mgamount remaining = ? mgelapsed time (t) = 33 yearshalf-life (T) = 11 years2nd solve for unknown

    *

  • Radioactive Decay Rates2nd solve for unknown (cont.)since there have been 3 halflives, then divide initial amount by 2 three times

    *

  • Radioactive Decay RatesExample: The half-life of cobalt-57 is 270 days. How much of a 5.000 mg sample will remain after 810 days?

    *

  • Radioactive Decay Ratessince half-lives are constant, radioisotopes can be used to determine the age of an object________________________________________ the process of determining the age of an object by measuring the amount of certain isotopescarbon-14 (half-life = 5730 years) dating used to measure the age of artifacts that were once part of a living organismother radioisotopes like uranium-238 (half-life = 4.5x109 years) to date older objects

    *

  • Nuclear Reactionsweve seen where one element can be converted into another through spontaneous emission of radiation (transmutation)elements can also be forced to transmutate by bombarding them with high-energy alpha, beta, or gamma radiation *

  • Nuclear Reactions________________________________________ the process of striking nuclei with high-velocity charged particlesRutherford did this in his experiment particle accelerators use electrostatic & magnetic fields to accelerate charged particles at high speedsFigure 24.13 Pg. 875*

  • Nuclear Reactions________________________________________ the elements with atomic numbers 93 & higher (right after uranium)all these elements were produced by induced transmutationthey are also radioactive

    *

  • Nuclear Energyto gain stability heavy nuclei can split into smaller nuclei________________________________________ the splitting of nuclei into fragmentsfission comes with a very large release of energyproduces 26 million times as much energy as the an equal amount of natural gas

    *

  • Nuclear Fissionnuclear power plants use fission to produce electricityby bombarding uranium-235 with neutrons*

  • Nuclear Fissioneach fission of uranium-235 releases 2 neutronsthese 2 neutrons can then cause another fission reactionwhich then produces 2 more neutronsthis selfsustaining process is called a ________________________________________amount of energy released can increase rapidlyhow atomic bombs work*

  • Nuclear Fis

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